1 00:00:43,16 --> 00:01:33,45 And who are. It has a while you. I thank you. Why. 2 00:01:33,9 --> 00:01:59,1 And who knew what he has or why I'm you haven't heard about the wonderful thing for me. 3 00:02:00,13 --> 00:02:17,19 Yep that my father gave me a set of cards you want to see you take it from me on that rely on the job the way you are. 4 00:02:18,2 --> 00:02:33,17 Let's go. Here we are. You. 5 00:02:34,98 --> 00:02:45,4 A lot talk a what's on your mind now that my friend knew the want you to put him through the works. 6 00:02:54,62 --> 00:03:00,57 Why man you still run on sixty. We'll have to bet feel up to ninety. 7 00:03:00,57 --> 00:03:25,49 Open your mouth you come right along with me the you are not talking let's put on an act for Miss him follow a slew of. 8 00:03:34,48 --> 00:03:49,9 Yeah. You really rare one. 9 00:04:00,41 --> 00:04:06,56 Minded who have a motion picture camera which is taking pictures through this window we use a soundproof moves 10 00:04:07,55 --> 00:04:13,27 when it's clear was it keeps the camera noise away from the microphone the camera is operated by a motor which runs 11 00:04:13,27 --> 00:04:19,83 exactly the same speed as a motor in the Sound Machine. Lulu It's hot in this movie. 12 00:04:19,83 --> 00:04:21,35 Let's get out on the set again 13 00:04:21,38 --> 00:04:28,41 and I was how the sound is picked up by the microphones on the stage sound waves are picked up by this wonderful 14 00:04:28,41 --> 00:04:36,62 mechanical air the microphone which is really a glorified telephone transmitter this microphone changes the sound waves 15 00:04:36,67 --> 00:04:40,04 into Aleck tickle a vibration which are amplified here 16 00:04:40,07 --> 00:04:47,03 and send along these wires to the mixer room the sounds from the stage microphones are mixed here so that the statue 17 00:04:47,34 --> 00:04:49,25 for the action in the production. 18 00:04:49,25 --> 00:05:02,78 Mr McNair's these actors through this window and hears them only through this current flow. 19 00:05:03,68 --> 00:05:10,15 Goal now that we've got the sound right. I was show you how it's amplified. 20 00:05:10,15 --> 00:05:23,39 Get ready for the power from the microphones is amplified about ten million times by these vacuum tube making the 21 00:05:23,39 --> 00:05:32,66 voyage current strong enough to operate the machines that photograph the sound so you follow me. 22 00:05:39,75 --> 00:05:45,03 This is the machine that is used to record the sound on film. 23 00:05:46,7 --> 00:05:54,38 This sounds sound is traveling at the same rate of speed as the picture found in the camera though the light bout has 24 00:05:54,38 --> 00:06:00,00 to thin metal strings stretched across this tiny slit on one side of the sled. 25 00:06:00,00 --> 00:06:08,15 The strong life while on the other is a film moving at exactly the same speed as the picture camera in the studio the 26 00:06:08,15 --> 00:06:15,28 greatly Apple a five voice current passing through these tiny light bows strings move them to classes a gather are 27 00:06:15,28 --> 00:06:19,17 further apart. Thus changing the size of the site. 28 00:06:19,17 --> 00:06:25,89 Therefore the light berries as it passes through this rapidly changing opening leaving a true photographic record of 29 00:06:25,89 --> 00:06:30,22 the voice currents on the film. 30 00:06:30,22 --> 00:06:40,84 Simple illness now let's look at the films after they've been developed Well here we are here are two negatives 31 00:06:40,84 --> 00:06:51,93 developed the next step is the print these two negatives onto a third piece of film will print the sound record first 32 00:06:52,52 --> 00:06:59,7 and then the picture record here we have a completed sound praying 33 00:07:00,26 --> 00:07:12,92 and we are now ready for projection this is the picture and sound projector one motor drives both the picture 34 00:07:13,43 --> 00:07:22,95 and sound equipment saying Let me illustrate this with a simple diagram this lamp illuminates the soundtrack on the 35 00:07:22,95 --> 00:07:30,33 film the light from the lab classes through the slit throwing a very narrow line of brilliant light on the soundtrack 36 00:07:31,44 --> 00:07:39,07 as the film runs right the marks on the soundtrack cause the light to increase 37 00:07:39,12 --> 00:07:46,62 and decrease this light in turn causes the current through the photoelectric cell to increase and decrease. 38 00:07:46,62 --> 00:07:54,07 Bus reproducing the electric vibration first created by the sound wave the current from the photoelectric cell is 39 00:07:54,07 --> 00:08:00,00 stepped up by the amplifier and then this amplified current is carried by wire. 40 00:08:00,87 --> 00:08:10,46 Along right through on the mystery and the say the connect with a loudspeaker. 41 00:08:12,09 --> 00:08:19,19 This is a typical layout of the stage that was to harness behind the screen the receivers connected to the heart 42 00:08:19,19 --> 00:08:26,75 and convert the electrical vibrations back in the Sound plays exactly the way the telephone receiver operates so that 43 00:08:26,75 --> 00:08:38,23 while the picture is being shown the sound which was recorded is reproduced in step with the picture of the screen is 44 00:08:38,23 --> 00:08:44,67 full of small holes so that the harnes Maybe place behind the screen to let the sound through this gives the illusion 45 00:08:44,95 --> 00:08:49,27 that the sound is coming from the image of the speaker. 46 00:08:50,96 --> 00:08:54,71 Talking they're going to your Q Your next onscreen by music 47 00:08:54,71 --> 00:09:12,23 and go try on is no more you write her a pop pop pop pop music machine when I know I know. 48 00:09:12,23 --> 00:09:39,9 Ok doing his stuff I can say for right there where you got me you know what you already know you look years Marty if 49 00:09:39,9 --> 00:09:48,86 you must stay on the screen with me. Suppose we get together was a little close harmony what he is saying hello. 50 00:09:50,43 --> 00:10:37,53 You relate you you. You go you know who's a news.